The instructions for flashing a ChatterBox device are nearly the same, no matter which type of device you have. Just be careful to choose the correct device type while flashing, and remember if it doesn’t work, you can safely re-flash the device.
All of your encrypted data, messages (if you keep message history), device and cluster settings are stored on the SD card, which is not affected by the flashing at all. You can even remove the SD card while flashing if you prefer.
Flashing can be done on the ChatterBox Firmware Flasher page.